3D self-assembly synthesis of hierarchical porous carbon from petroleum asphalt for supercapacitors

Abstract

A facile and scalable three-dimensional self-assembly template synthesis of hierarchical porous carbon method is developed. During the synthesis, KCl with face-centered cubic crystal is adopted to guide the growth of 3D porous carbon networks. Remarkably, the intimate interconnect porous feature not only significantly speeds up the electron transfer via shortened ion diffusion distance, but also exposes the electrochemically accessible active sites through ultrahigh surface area up to 3581 m2 g−1. As electrodes for button type supercapacitors, the HPC electrode shows a high capacitance of 277 F g−1 at 0.05 A g−1, superior rate performance of 194 F g−1 at 20 A g−1 and excellent cyclic stability of 95.1% after 10000 charge and discharge cycles at 2 A g−1 in 6 M KOH electrolyte. Furthermore, the HPC based symmetric supercapacitors possess high specific energy density of 14.2 Wh kg−1 at a power density of 445 W kg−1 operated in the wide voltage range of 1.8 V in the Na2SO4 electrolyte. This work opens up a facile way for efficient and scaled-up production of low-cost electrode materials with high performance for other energy storage devices.